It seems like meat grinder motors have to put out a lot of torque, it would probably take some creative gearing to transfer the high RPM output of a juicer to this application. I suppose it could be done, though.

The first few turns will be very tight, but once it starts turning a few times it will loosen up. While doing this the jar should be upside down with a little oil under the rubber plastic motor coupling to lubricate the mixie mixer grinder jar blades.